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1030 Holley 3 Barrel

18K views 11 replies 9 participants last post by  CDN SS 
#1 ·
I just got a Holley 3 barrel at the swap meet and am trying to get a little information on it. It is a list number 4604S, which I believe means it is a 1030. It has 2 tubes that dump fuel to the secondaries. There is also a weird looking squirter that comes from the primary side and shoots fuel to the secondaries. Someone has also added gears to make it a 1:1 mechanical secondary. Someone has also added a secondary metering plate that looks like there is no way that it will work. It is part number 4519. Did Holley make a secondary metering block that would allow you to convert one of these 3 barrels to run rear jets? I feel sure that this one is not the correct one. Does anyone know the part number of the correct one? Thanks
 
#2 ·
3-bbls. came in two cfm ratings,950&1050,the gear drive set-up and dual squirter set-up was a popular 'band-aid' for the time period before the double-pumpers hit the scene.popular but not safe! gear drives were known to stick open! they never came with metering blocks just plates. find a vacuum pod for secondaries and get a kit from summit or jegs,they still list them. 3-405 hope this helps. as long as you like to tinker these are nice carbs, just hold-on!! good luck.
 
#3 ·
That gear drive and squirter setup is the quickest way I know of the cut your gas mileage in half. One 250 mile run and two tanks of gas later, the setup came right back off and went into the garbage. Those old three barrel Holleys are more of a nostalgia thing these days. Not many cars need a carb that big. Motion Performance was putting them on everything for a while.
 
#4 ·
I still have one too. I ran it on a 427 years ago in my Camaro. Ran well overall. A buddy has one on a 455" Pontiac that has back to backed faster than several other 750-850 sized carbs on it.

I removed the large *tripower* type vacuum can and installed a regular small one. In my younger *street competition* days I could easily pass it off as a 780 vacuum carb.

The gear and squirter setup is definitely some cool nostalgia stuff.....not sure how practical or needed it is.

They aren't bad to play with and I can guarantee you they can easily run deep into the 10's.

Plus they are just weird and cool!

This one isn't mine..but gives folks an idea if they have never seen one.



JIM
 
#5 ·
The 3-barrel Holley carb created a lot of excitement when they were introduced in the mid 1960's. They were unique but were a bear to tune. The gear drive secondary setup and tube type squirters were popular to change vacuum secondaries to 1:1 secondary opening, but they did not work well, especially on street-driven vehicles. The gear drive was totally wrong for the 3-barrel carburetor as that was just too much secondary throttle to open early in the throttle and the engine (even a well built race engine) would usually fall on its face off the line. OK, it might work in a large cubic inch engine in a 2000 lb. chassis, but that is about it. The gear drive also tended to bind and would either stick open and/or would cause excessive wear on the throttle shafts.

The vaccum diaphram for the 3-barrel secondaries was much larger than the diaphram used in vaccuum secondary 3-barrel carbs. This was necessary to handle the additional weight of the secondary throttle plate. You will probably have a heck of a time finding the correct vacuum setup for this carb. Interesting carb though and makes an excellent conversation piece.
 
#7 ·
Ive used several on 496 and 540 BBC builds with dual plane intakes and as long as you know how to tune they are not hard to get running really well
Id say 70% of the guys I run into can,t tune,use a vacuum gauge timing light, find TDC or time an engine or read plugs or a fuel/air meter, adjust valves or check fuel pressure or exhaust temps with an IR temp gun, , even tuning a standard 750cfm Holley correctly seems beyond their skill level so if you hear that the 950 3 barrels difficult, keep that in mind
 
#8 ·
Thank you for the replies everyone. I think I will try it on my 468 build for my '57 Ford Gasser. I am actually running the 950 version on an 11:1 solid roller 427. There is absolutely no bog at all and it runs outstanding. I think I may re-build this carb and see what it will do. I only gave $40 for it, so I don't have much to lose. I think I will take the gear drive set up off, however.
 
#12 ·
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